https://abcnews.go.com/US/fbi-monitor-violent-online-threats-light-joker-premiere/story?id=66031356
The FBI has received tips of threatening posts on social media calling for "unspecific mass shootings" linked to the release of the new psychological thriller, "Joker," starring Oscar-nominated actor Joaquin Phoenix that will hit theaters this Friday, according to a joint intelligence bulletin obtained by ABC News.
These threats have been circling online platforms since at least May 2019, but give no information indicating specific or credible threats to particular locations or venues, the bulletin said.
Some of the threats did contain references to a primarily online group called the involuntary celibate community, or Incels, and a subset that refers to itself as "Clowncels." However, the intelligence community doesn't necessarily regard the group as a whole as a violent one.
"While many Incels do not engage in violence, some within the community encourage or commit violent acts as retribution for perceived societal wrongdoing against them," the bulletin said. "Some Incel attackers have claimed inspiration from previous mass shooters."
(Score: 3, Interesting) by Arik on Friday October 04 2019, @08:59PM
However it's clear that it's a large and ongoing problem just from the cases that are reported.
It's been going on for years too, here's an article from Time back in 2010: http://content.time.com/time/world/article/0,8599,1985834,00.html
In that case there 5 such attacks reported in just over a month.
Wikipedia has a page that references several, only from 2010-2012: https://en.wikipedia.org/wiki/School_attacks_in_China_%282010%E2%80%9312%29
But the attacks haven't stopped. Here are more recent examples that did receive reporting:
https://www.bbc.com/news/world-asia-china-43921567
https://www.newsweek.com/seven-children-killed-and-12-others-wounded-mass-stabbing-attack-china-904058
https://www.cbsnews.com/news/china-school-attack-in-hubei-leaves-8-elementary-school-children-dead-today-2019-09-03/
https://www.scmp.com/news/china/society/article/3025383/ten-pupils-injured-knife-attack-chinese-primary-school
If laughter is the best medicine, who are the best doctors?